SpeedTrees are now owned by a different organisation than when the change from TS12 to T:ANE occurred and N3V were forced, by their license agreement, to upgrade to the new (v6) version. V6 was incompatible with the version (v5) used in TS12. So perhaps there is no license requirement to upgrade this time (??). The change from v5 to v6 drove a few tree creators away.
It has been reported in these forums that the new v8 SpeedTrees catalogue has fewer trees for some regions, such as here down-under, than the v6 catalogue does so I, for one, would not be a happy route creator.